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列当俗称独根草,在我县主要危害食用型向日葵。发生面积约在5—6万亩,占播种面积的80%以上,减产在30—50%,严重地块绝收。因此,搞好向日葵列当防治,对促进向日葵生产有着重要意义。一、危害情况。列当在向日葵开花时陆续出土,开花盛期也是危害盛期,它直接影响花盘的增大和籽粒的形成,使经济产量降低(见表)列当危害调查表
Columns commonly known as kohlrabi, in my county mainly endanger the edible sunflower. The occurrence of an area of about 5-6 million mu, accounting for more than 80% of sown area, cut in 30-50%, a serious block must. Therefore, to do a good job sunflower prevention and control, to promote sunflower production is of great significance. First, the damage situation. Column when flowering in the successive unearthed sunflowers, blooming peak is also endangering period, it directly affects the increase of disk and grain formation, reducing economic output (see table) as a hazard questionnaire